Powerpoint Copilot generates unrelated and nonsensical slides

I have been using Copilot for Office in a case that seemed perfect, namely generating slides in PowerPoint from a Word document.

I got quite strange results, i.e., the first version of the slides is good, if I then ask for a modification such as reducing the number of slides (which Copilot in the chat seems to have understood correctly), the result was repeatedly the same, i.e., it proposes me nonsensical slides about the history of Istanbul (!?!).

I don't have any material on Istanbul nor have I ever researched it, so I think (I hope) that it is some kind of Easter Egg popping up when Copilot doesn't understand the command, otherwise it would be a really serious problem. In the screenshots you can see that Copilot interpreted the command correctly, but the result is completely wrong.

I repeated the same sequence several times, starting from scratch, and the result was always the same, i.e., slides about Istanbul.

What's happening here?